This invention relates generally to display apparatuses and, more particularly, to display apparatuses capable of displaying different images.
Display apparatuses capable of displaying different images are becoming increasingly popular, especially as advertising devices. Using such a display apparatus, a media group can frequently change the advertisement image on display. This gives the media group the ability to advertise a client""s product or services using many different images. It also gives the media group the ability to use the display apparatus to advertise the products and services of a large number of different clients.
The most cost-efficient and reliable form of such display apparatuses employ a roll of film to which has been applied a plurality of individual still images. The roll of film is disposed within a display structure having two or more vertically spaced-apart parallel rollers. The space between the rollers provides a visual image display location. When a particular still image is desired to be displayed, the film is scrolled until the desired image is properly centered within the visual display location. Typically, the roll of film is scrolled using one or more scrolling motors controlled by some form of sensor/controller.
There are several problems with presently available display apparatuses of the type described above. One problem arises from the fact that the sensor/controller typically controls the scrolling of the film by attempting to xe2x80x9ckeep trackxe2x80x9d of the relative position of each still image on the film. For example, a typical controller is programmed to note that the twelfth still image on a roll of film, is just that, the twelfth image on the roll of film. If the controller believes that the image presently being displayed at the display location is the fourth still image on the roll of film, and that the twelfth still image is desired to be displayed at the display location, the controller controls the scrolling of the film until the film is advanced by eight still images. The problem with this method of controlling the scrolling of the film is that, if the controller mistakenly believes that the image being displayed at the display location is the fifth still image (instead of the fourth still image), the controller will scroll the film only-seven still images in its attempt to place what the controller believes to be the twelfth still image within the display location. However, because the controller was xe2x80x9cmistakenxe2x80x9d regarding what still image was initially being displayed within the display location, the scrolling of the film by seven still images causes the eleventh still image to be displayed at the display location (not the twelfth still image). What is more, once the controller makes such a mistake as to where the film is with respect to the display location, it will remain xe2x80x9cmistaken,xe2x80x9d until the mistake is realized by an operator.
Another problem with display apparatuses of the type described above is that the image displayed at the display location is static, and therefore does not necessarily attract attention. While the film is being scrolled to a new display image, the sign catches the eye of the observer, but once the image is properly centered at the display location, the image becomes stationary and is no longer interesting to the eye of the observer.
A third problem with such display apparatuses has to do with the most common way of braking the scrolling means to stop the scrolling of the apparatus when the desired still image has becomes properly centered within the display location. Most scrolling mechanisms employ some form of mechanical brake to slow and stop the scrolling of the film. However, mechanical brakes are prone to wear, and thus require frequent maintenance and/or replacement.
Accordingly, there is a need for a display apparatus capable of displaying different images which avoids the aforementioned problems with the prior art in an economically efficient and operationally reliable way.
The invention satisfies this need. The invention is a display apparatus comprising (a) a display structure, having a visual display location for displaying a desired still image, (b) a roll of film having at least two still images set forth thereon, each image being displayable at the visual display location, (c) scroll means for alternatively scrolling the film forwards and backwards to align a desired image at the visual display location, (d) control-means for controlling the scroll means to align a desired image at the visual display location, and (e) oscillating means for oscillating an image displayed at the visual image location.
In a preferred embodiment, the control means includes means for identifying individual still images on the film separate and apart from that still image""s relative location along the length of the film.
In another preferred embodiment, the scroll means includes braking means which rely principally upon dynamic braking to slow and eventually stop the scrolling of the film.